The Laterality of Handedness, Foot Preference and Foot Overlapping a Dolescent S Ection

Original Article The Laterality of Handedness, Foot Preference and Foot Overlapping A dolescent S ection

Rajeshwari.C.Eligar

Abstract foot overlapping. The data which were collected were subjected This study was aimed at the distribution, the frequencies and the to tabulation and statistical analysis and those were tested correlation between the laterality of handedness, arm folding, for statistical significance. The Chi square test was used with digital interlocking, foot preference and foot overlapping. The the paired ‘T’ test. Male subjects exhibited a highly significant subjects who were selected for this study were teenagers between correlation between handedness and digital interlocking (P<0.01) the age group of 13 to 15 years. The study was conducted at Female subjects showed a highly significant correlation between Belgaum city which is situated in North Karnataka, India, during handedness and digital interlocking (P<0.005) 2000. There is no relevant information in the literature regarding A highly significant correlation existed between digital interlocking a similar study which was done in this part of the country. The and arm folding in both the sexes (P<0.0001). A significant population here exhibits a wide diversity in cultural and traditional correlation was seen between handedness and foot overlapping lifestyles and hence this study was taken up. Personal data was (P<0.005) in both males and females. Both females and males collected from the subjects by providing them a questionnaire. showed a significant correlation between foot preference and Various tests were conducted to determine the handedness, the foot overlapping (P<0.01). laterality of arm folding, digital interlocking, foot preference and

Key Words: Laterality; Handedness; Foot preference; Cerebral dominance; Asymmetry

KEY MESSAGE

n Several studies regarding handedness have suggested that left-handers have higher than expected rates of neurological disorders including epilepsy, stuttering, dyslexia and other learning disabilities.

n Recent studies have also shown that left-handedness and non-right-handedness is associated with sudden cardiac death. This may be attributed to a sympathetic imbalance which results in ventricular arrhythmia.

n An association between left-handedness and immune diseases and migraine has also been studied.

n A link between inflammatory bowel diseases and left-handedness was also suggested.

Introduction their possible uses in genetics and in population comparisons. The phenomenon of lateral dominance has a close relationship They are easily determined manifestations of cerebral dominance. with the structure and function in the animals of all Phyla. A study This is apparently a unique evolutionary development in man, on children who were aged 11 years, which was conducted at which becomes clinically important in the diagnosis of strokes and London [1], concluded that non right handers had a significant aphasias. association with the deficits of performance on certain standardized attainment and ability tests. Non right handedness was associated MATERIALS AND METHOD with “poor speech” as was assessed by teachers in schools. The The volunteers for this study were selected from 1) Phoenix Public teachers also reported that the non right handers had a “poor School and 2) Smt. Annapurnadevi Hiremath English Medium control of the hands”. It has been commented that the incidence school of Belgaum city, who were between the ages of 13 to 15 of left-handedness is more in males than in females [2]. It was years. The total number of subjects who were included in the study also stated that the left-handedness was more in the younger was 200. Care was taken to include only healthy subjects. Those age group than in the older adults. A study on foot overlapping with any disability or a deformity of the upper or lower limbs were (leg crossing) in German samples [3] concluded that 62% of the excluded from the study. Out of them, 112 were boys and 88 population were right leg crossers, 26% were left leg crossers and were girls. The subjects were requested to answer a questionnaire that 12% were ambilateral. Foot overlapping is correlated to some which included questions about their personal information. Each extent with footedness and handedness. Digital interlocking, arm subject had to mention the family history of left handedness folding and handedness have a place in human biology, far beyond and footedness in the questionnaire. Each subject was carefully

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observed and the hand which was used by each one of them to Males Females pick up the questionnaire was noted. Various tests were conducted RD % LD % RD % LD % to determine the handedness, arm folding and digital interlocking, foot preference and foot overlapping and the observations were Digital RD 97 86.7 1 0.8 70 79.5 1 1.2 interlocking recorded. LD 11 9.9 3 2.6 13 14.8 4 4.5 Arm folding RD 83 74.1 2 1.8 59 67.04 3 3.5 TESTS FOR HANDEDNESS LD 25 2.3 2 1.8 24 27.3 2 2.3 The tests for handedness were as follows: Foot RD 84 75 1 0.8 58 65.9 1 1.1 overlapping (a) Picking up the pins and pinning them on the cushion LD 24 21.5 3 2.7 25 28.4 4 4.6 (b) Cutting the paper with scissors Foot RD 108 96.4 2 1.7 83 94.3 1 1.1 (c) Hammering on a nail preference LD 0 0 2 1.2 0 0 4 4.6 (d) Handwriting (e) Making a personal impression of one’s own handedness. [Table/Fig-3]: Comparison of Handedness and its paired distribution with the other variables studied THE TESTS FOR FOOT PREFERENCE The subjects were asked to kick a football towards a goal, from a distance of 10 meters, in an attempt to make a score. An Males Females assessment was made on how accurately each subject aimed at RD % LD % RD % LD % the goal and how hard he/she kicked the ball. They were observed Handing RD 97 86.6 1 0.9 70 79.5 1 1.1 carefully to assess as to which foot was first preferred to kick the LD 11 9.8 3 2.7 13 14.8 4 3.6 ball. After each one of them used both the legs, proper distinction Arm RD 81 72.4 4 3.5 55 62.5 5 5.7 was made between the dominant and non-dominant foot, by folding observing the comfort, accuracy and the hardness with which the LD 17 15.2 10 8.9 16 18.2 12 13.6 ball was kicked by each foot. Foot RD 73 65.2 12 10.7 48 54.6 10 11.4 overlapping LD 25 22.3 2 1.8 23 26.1 7 7.9 THE TESTS FOR ARMFOLDING, DIGITAL Foot RD 97 86.6 1 0.9 71 80.6 1 1.1 preference INTERLOCKING AND FOOT OVERLAPPING LD 13 11.6 1 0.9 13 14.1 3 3.5 The subjects were demonstrated about the exercises i.e. arm [Table/Fig 4]: Comparison of Digital interlocking and its paired folding, digital interlocking and foot overlapping and they were distribution with the other variables asked to mimic the exercise. The arm, digit or foot which was on top, was considered as the dominant one.

ETHICS Males Females The study was conducted on teenage student volunteers in the RD % LD % RD % LD % local schools. The permission to conduct the study was granted Hand RD 83 74.1 25 22.3 59 67 24 27.3 by the heads of the institutions. The willingness of the parents of LD 2 1.8 2 1.8 3 3.4 2 2.3 each student was taken into consideration before conducting the Digital RD 81 72.3 17 15.2 55 62.5 16 18.2 study. interlocking LD 4 3.6 10 8.9 5 5.7 12 13.6 RESULTS AND TABULATIONS Foot RD 73 65.2 12 10.7 45 51.1 16 18.2 overlapping LD 12 10.7 15 13.4 13 14.8 14 15.9 SL No. No. No. No. % No. Function No. Tested RD %RD LD %LD AL AL Foot RD 84 75 26 23.2 60 68.1 24 27.3 preference 1. Handedness 112 108 96.45 4 3.55 – - LD 1 0.8 1 0.8 3 3.4 1 1.2 2. Foot preference 112 110 98.20 2 1.80 – – [Table/Fig 5]: Comparison of Arm folding and its paired distribution with other variables studied 3. Arm folding 112 85 75.90 27 24.10 – – 4. Digital interlocking 112 98 87.50 14 12.50 – – 5. Foot overlapping 112 85 75.90 27 24.10 – – Males Females [Table/Fig-1]: Frequencies of Male subjects with distribution of lateral dominance for each of the parameters studied RD % LD % RD % LD % Hand RD 84 75 24 21.4 58 65.9 25 28.4 LD 1 0.9 3 2.7 1 1.1 4 4.6 SL No. No. % No. % No. % No. Function No. Tested RD RD LD LD AL AL Digital RD 73 65.2 25 22.3 48 54.6 23 26.1 interlocking 1. Handedness 88 83 94.30 5 5.70 – – LD 12 10.7 2 1.8 10 11.4 7 7.9 2. Foot preference 88 84 95.50 4 4.50 – – Arm folding RD 73 65.2 12 10.7 45 51.2 16 18.2 3. Arm folding 88 62 69.30 27 30.70 – – LD 12 10.7 15 13.4 13 14.8 14 15.9 4. Digital interlocking 88 71 80.70 17 19.30 – – Foot RD 86 76.8 24 21.4 58 65.9 26 29.5 preference 5. Foot overlapping 88 27 64.77 31 35.23 – – LD 0 0 2 1.8 1 1.1 3 3.5 [Table/Fig-2]: Frequencies of Female subjects with distribution of lateral [Table/Fig 6]: Comparison of Foot overlapping and its paired dominance for each of the parameters studied distribution with the other variables studied

422 Journal of Clinical and Diagnostic Research. 2011 June, Vol-5(3): 421-424 www.jcdr.net Rajeshwari C.Eligar, Laterality of handedness, foot preference and foot overlapping

Males Females the right hand. “Cerebral dominance is a distinctive biological attribute of man, and as far as it is known, it is either absent or RD % LD % RD % LD % poorly developed in any other mammal” [11] The comparison of Hand RD 108 96.4 0 0 83 94.3 0 0 the frequencies of handedness and digital interlocking in [Table/ LD 2 1.7 2 1.7 1 1.1 4 4.5 Fig 3] shows that the right handed male tends to be 89.8% right Arm folding RD 84 75 1 0.8 60 65.9 3 3.4 dominant for digital interlocking. 25% of the left handed males tend LD 26 23.2 1 0.8 24 27.2 1 2.2 to be right dominant for digital interlocking. 98.8% of the males Digital RD 97 86.6 1 0.8 71 79.54 1 1.1 who were right digital interlocking, were right handed. 78.57% of interlocking the left digital interlocking males were also right handed. Among the LD 13 11.6 1 0.8 13 14.77 3 3.4 right handed females, 84.3% tended to be right digital interlocking Foot RD 86 76.7 0 0 58 65.9 1 1.1 and among the left handed females, 20% tended to be right digital overlapping LD 24 21.41 2 1.7 26 27.2 3 3.4 interlocking. 98.5% right digital interlocking females were right [Table/Fig 7]: Comparison of Foot preference and its paired handed and 76.4% of the left digital interlocking females were distribution with the other variables studied right handed. Both males and females showed a highly significant correlation between handedness and digital interlocking (P< 0.01 DISCUSSION and P<0.005 respectively). Handedness and digital interlocking Somatic asymmetry is well known and widespread in the animal exhibited some correlation, according to others [12]. Others kingdom. It was suggested by some authors that sex hormones differed from this opinion. They found that there was no correlation may affect the growth of the two sides of the body differentially. It between digital interlocking, arm folding and handedness [13] .The was reported that in right-handers, the right foot was more often present study did not find any correlation between handedness larger in males, while the left foot was larger in females [4]. There and armfolding in either of the sexes.(P>0.1). Some have argued was a great enthusiasm and interest regarding this measure by other that the lateralization of the function enhances the cognitive authors, which arose from a possibility that the brain hemispheres capacity and the efficiency of the brain, thus countering the followed a parallel pattern. Somatic asymmetry appears early in ecological disadvantages of the lateral biases of behaviour [14]. foetal life, thus suggesting a prewiring of the brain for one pattern or There was a suggestion of a link between left handedness and another before birth. A study reported that the testicular or breast the risk of inflammatory bowel diseases [15]. The asymmetry of volume asymmetry were significantly different in human males and the thyroid lobe volume in three dimensional ultrasound images females. Among the males, there was a higher frequency of right- showed that there was an association between the handedness larger individuals, while among the females, there were more left- of the subjects and the position of the oesophagus [16]. Some larger subjects [5]. Earlier researchers had suggested that there workers contended that there was a correlation between digital was a generalized dimension of motor laterality, at least among interlocking and armfolding [17]. The same findings were obvious the males, from the inference of a study, where a majority of the in the present study as well. [Table/Fig 4] depicts the comparison people exhibited a right dominance for variables like handedness, of the frequencies of digital interlocking with various parameters. footedness and eyedness [6]. The current study shows an ipsilateral Both males and females exhibited a highly significant correlation correlation between handedness and foot preference. [Tables/ (P<0.0001). On the contrary, there is no correlation between digital Fig 1 & 2] show the correlation of handedness with the different interlocking and foot overlapping in both the sexes. Both males parameters. Left handed females showed a 20% tendency of using and females combined together, showed a significant correlation the right foot. Right footed females had a 98.8% chance of using between digital interlocking and foot preference (P<0.001). [Table/ the right hand. Left footed females had a 100% chance of using the Fig 5] shows the comparison of armfolding with the frequencies of left hand. Left handed males had a 50% chance of using the right various parameters and this shows a significant correlation between foot. Left footed males had a 50% chance of using the right hand. arm folding and foot overlapping in both males and females Both males and females showed a significant correlation between (P<0.001). On the other hand, there was no correlation between arm handedness and foot preference (P<0.001). A difference of opinion folding and foot preference in both the sexes. [Table/Fig 6] shows on this matter was indicated in the study on the foot and eye foot overlapping and its correlation with different parameters. It was preference in adults, their relationship with the hand, sex and age observed that neither males nor females showed any correlation [7]. There is a higher proportion of crossed hand-foot preference between foot overlapping and foot preference. In [Table/Fig 7], the in men than in women. It has been asserted that cross-dominance comparison of foot preference with various parameters showed is advantageous in sports which require side-on-stances, for eg: no correlation between foot preference and foot overlapping. A base-ball, cricket, golf [8]. However, a recent South African study high prevalence of left handedness has been revealed in geniuses found that cricketers were not more likely to have cross-dominance like Julius Caesar, Napoleon, Leonardo da vinci, Michaelangelo, than the normal population [9]. Cultural pressures determine the Picasso, Chaplin, Lewis Carroll, Benjamin Franklin, several famous socialization of handedness in many societies. More often, females comic actors and four presidents of the United States. In a research are compelled towards the conformity of right handedness. The paper, it was concluded that the area of handedness was filled explanation of the laterality of digital interlocking, arm folding, foot with grey spots- there were no definite conclusions nor any definite preference and foot overlapping is a controversial topic. There proof of anything. The only fact was that for some reason, 10% is merely a partial genetic control of digital interlocking and arm of the world’s inhabitants preferred to use the left hand over the folding [10]. When individuals clasp their hands by entwining the right. In trying to explain this, the reasoning behind handedness fingers in a natural way (digital interlocking), they can be termed centers around protection, convenience, genetics, environment, as ‘R’ individuals, if the fingers of the right hand remain above brain hemisphere dominance, the birthing process and the effect that of the corresponding ones of the left hand. Others are called of the body’s chemical levels. Which one is the right one? At this ‘L’ individuals if the fingers of the left hand remain above that of point, it is hard to tell [18] .

Journal of Clinical and Diagnostic Research. 2011 June, Vol-5(3): 421-424 423 Rajeshwari C.Eligar, Laterality of handedness, foot preference and foot overlapping www.jcdr.net

ACKNOWLEDGEMENTS [10] Thomas N,G. Harden L,M. Rogers G,G. Visual evoked potentials, reaction times & eye dominance in Cricketers. J Sports Med Phys I sincerely and gratefully acknowledge the help and support of the Fitness., Sep 2005;;45(3):428-33. Principal of Shrimati Annapurnadevi Hiremath English medium and [11] Freire Maia A. and Jorge de Almeida . Handclasping and armfolding Kannada medium schools of Belgaum city. I further extend my among African Negroes. Human biology., 1966;38;175-79. gratitude to the student volunteers and their parents for their co- [12] Geschwind, N, and Levitsky, W. Human brain:Left-right asymmetries in temporal speech region. Science.,1968;161:186-87. operation in conducting this study. [13] Rhoads J.G.and Albert Damon. Some genetic traits in Solomon island population. Handclasping, armfolding and handedness. Am J. phys. References Anthrop.,1973; 39;179-84. [1] Calnan M. and Richardson K. Developmental correlates of handedness [14] Mc. Manus I.C. and Mascie Taylor C.G.N. Handclasping and armfolding: in a national sample of 11 years olds. Annals of human biology,1976;vol A review and a genetic model. Annals of human biology.1979;,Vol 3(4):329-42. 6:527-58. [2] Chris C. Plato Kathleen M. Fox and Ralph M. Garruto. . Measures [15] Giorgio V. Lesley, J. Rogers Survival with an asymmetrical brain. of lateral functional dominance: Hand dominance. Human biology. Advantages and disadvantages of cerebral lateralization. Behavioral 1984;,vol 56(2):259-75. and brain sciences.,2005; 28:575-633. [3] Reiss M. A study of leg-crossing in a German sample. Anthropol Anz., [16] Morris, D L. et al., Inflammatory bowel disease and laterality: is left Sep 1995 53(3):263-68. handedness a risk?. Gut.,2001; 49:199-02. [4] Levy, J. & Levy, J.M. Human lateralization from head to foot: sex [17] Michael Ying and Dennis M.C.Yung. Asymmetry of thyroid lobe volume related Factors Science., 1978;200:1291-92. in normal Chinese subjects: Association with handedness and position [5] Kimura,D. . Body asymmetry and intellectual pattern. Person. Individ. of esophagus. The Anatomical Record.,2009; 292:169-74. Diff.,1994; vol 17 (1); 53-60. [18] Kobyliansky E., Micle S. and Arensburg B. Handedness, handclasping [6] Brown E.R., Taylor P. Handedness footedness and eyedness. Percept and armfolding in Israeli males. Annals of human biology.,1978; Vol.5 Mot Skills.,1988; Feb 66 (1);183-86. (3):247-51. [7] Dargent Parz C., De Agostini M., Mesbah M., Dellatolas G. [19] Molly kalafut.. Left-handedness nature or nurture, blessing or curse?. [8] Foot and eye preference in adults: relationship with handedness, sex Retrieved from 2005 www.molly.kalafut.org/lefthanded/lefthanded. and age. Cortex., Sep 1992; 28 (3):343-51. html. [9] Brian Ariel. Sports vision training: An expert guide to improving performance by training the eyes. Retrieved from http://www.pponline. co.uk/encyc/0148.htm.

AUTHOR: NAME, ADDRESS, TELEPHONE, E-MAIL ID OF THE 1. Dr. Rajeshwari.C.Eligar CORRESPONDING AUTHOR: Dr. Rajeshwari.C.Eligar, Associate Professor, Dept of Anatomy, NAME OF DEPARTMENT(S)/INSTITUTION(S) TO WHICH Karnataka Institute Of Medical Sciences, Hubli, Karnataka, India THE WORK IS ATTRIBUTED: Phone: 9448492566 Dept of Anatomy, Karnataka Institute Of Medical Sciences, E-mail: [email protected]; Hubli, Karnataka, India DECLARATION ON COMPETING INTERESTS: No competing Interests.

Date of Submission: Feb 15, 2011 Date of Peer Review: Apr 03, 2011 Date of Acceptance: Apr 03, 2011 Date of Publishing: Jun 13, 2011

424 Journal of Clinical and Diagnostic Research. 2011 June, Vol-5(3): 421-424